PDA

View Full Version : Electric Hydro Mr2 Power Steering


TougeLabs
03-31-2008, 12:49 AM
I was ust going over this idea with brewster240 about doing a electric power steering setup in my car. Was wondering if anyone is running one

Heres the perks

Pump wont rob any power
can run it with stock alternator
speed sensitive power steering
and really cool

racepar1
03-31-2008, 12:55 AM
The dent sport garage s-13 has that set up. They mounted it on the passenger's side where the kick panel used to be. Sorry, but nothing new or groundbreaking here.

!Zar!
03-31-2008, 04:41 AM
It's been done.

More commonly with Renault electric ps pumps.

Search the FC forums. It's pretty common over there.

TougeLabs
04-01-2008, 12:56 AM
o racepar1 i know this is not new i was not trying to come across like i had an original idea...I was just looking for some insight on the project, I have been trying to source a hydro but had zero luck.
From what ive been reading the mr2 one has a flow sensor that adjusts to how hard it is to turn the wheel at diff speeds kinda interesting. I went with a meziere elec water pump so i figured i would go this route as well.
thanks though guys ill keep you updated...

projectdrifter
04-01-2008, 01:09 AM
i had looked into a similar setup.. maybe dent sports can chime in.

HyperTek
04-01-2008, 03:39 AM
hmm i never looked into that stuff..

tons of first gen mr2 at my local yards, i presume they have it too?

DJ_Sunrise
04-01-2008, 05:24 PM
I work parts at a Toyota dealership. Let me know if you need anything. part numbers, parts, compatibility, etc etc

-Bart

TougeLabs
04-05-2008, 08:14 PM
Ok i picked one up hopefully its what i was looking for going to the yard to pick it up monday.
Anyway I will take piks and everything this system is going to be awesome cant wait to start on the project after my cage is done

CAPoweredS14
04-05-2008, 08:32 PM
I'm also very interested in this as my PS pump seems to be going out on my CA and would like something new. I also like the idea of it freeing up load from the crank. I don't mind making more SS lines! Keep us/me posted man.

TougeLabs
04-05-2008, 08:36 PM
No problem man.

GSXRJJordan
11-03-2008, 01:15 PM
Sorry to bump this old thread, but I've been looking into this very seriously, as I'd love to stuff it under my front fender on the drivers side behind a cooler since the MR2 pump is so light (and keep my engine bay super clean, no wires/reservoirs, etc).

Pumps:
There are a lot of hydro-electric pumps - older Euro cars have them, and the Subaru SVX had one - but the 2nd gen MR2 pump is the smallest/lightest/most reliable. They can be sourced from $50-$100 apparently, although I have yet to purchase one.

Lines:
Same as a regular power steering pump - high pressure from the pump to the rack, low pressure from the rack to a cooler (cause, why not?), low pressure from the cooler back to a reservoir (which just has to be higher than the pump, so you could still stuff it low in the car), and of course low pressure from the reservoir to the pump. Regular SS braided line is not the best idea for the high pressure line, because of the ridiculous pressures generated (up to 2000psi), but there's tons of high-pressure lines (some rubber and some rubber/SS) you can use. High pressure fittings must also be used, duh.

Power:
This is where I got surprised - the MR2 pump pulls between 70A and 90A at full power - that's more than your alternator can generate! This means the battery's being used as a buffer, but still, that's a lot of juice, especially if you have a sound system also. Most people run either a 80a-100a self-resetting circuit breaker or just a fuse, and >8ga wire.

Control:
This is where it gets tricky. The MR2 used a bunch of sensors that interfaced with a power steering control box vary the input voltage to the pump, less voltage = less pressure generated. These include steering angle (pump generates max pressure at full lock, so if you keep your wheel at full lock for a while you'll burn out the motor - the stock control unit keeps an eye out for this - also gives you more pressure when you turn the wheel faster), vehicle speed, and something else.

A full listing/tutorial for installing the OE system can be found here.
Toyota MR2 Power Steering System (http://www.evalbum.com/tech/mr2_powersteering.html)

Another interesting find was some guys using the MR2 pump with their own control stuff - can't find the full writeup, but this is their page:
Selecting a Power Steering System (http://www.cameronsoftware.com/ev/EV_PowerSteering.html)

I'm concerned with a couple things - first, that it's going to be a bitch to find all of the required electrical components to get the Toyota OE setup to work right. Second, that if I hook it up at full power that it's going to be overcorrected and draw far too much current to be efficient. Most people that use them at full power all the time are racers, and I don't think I want to make that huge of a trade-off because my car sees street driving 99% of the time.

I was hoping any others (Luke asked Bill @ DentSport to chime in, he's the only other person I know of) that have experience with the system can tell me about the control aspect.

Bigsyke
11-03-2008, 01:48 PM
Good work man, looks like it would be a pretty easy install once your source the lines/fittings and pump.

The biggest and most important would be controlling the ammount of power it uses. If you have disected a PS pump the inner fins are so small and the draw isnt as large as the alternator would draw.

GSXRJJordan
11-03-2008, 02:27 PM
My first thought was a simple potentiometer - you could reduce the voltage going to the pump from 13.5V all the way to 0V, but not if the motor's drawing 70 fucking amps! You'd need a PWM controller connected to a relay, but relays that switch fast enough to keep up with a PWM controller and also can handle 70A DC are expensive.

I'll probably find a PWM controller and wire in a knob (for max voltage, so I can fine tune how much pressure is sent at max) and a steering column sensor (so when you're not steering the pumps not on), and see if I fry a starter relay.

soreballz
11-03-2008, 03:00 PM
^Upgrade to a Quest alternator. =]

GSXRJJordan
11-03-2008, 03:06 PM
Haha I'd wire in a couple capacitors to help out with the quick on/off DC loading before I upgraded the alt... it'd be easier on the whole electrical system.

jandysil80
11-03-2008, 03:57 PM
another alternative to the quest alternator swap is to have your stock one upgraded. I recently had my stock SR alternator rebuilt to 150 amps, big upgrade over stock 80 amps. Check out Maniac Electric Motors.com High Output Alternators | Fan Motor Assembly | Power Cable Kits (http://www.maniacelectricmotors.com/)

GSXRJJordan
11-03-2008, 04:06 PM
You guys are totally missing it - I'm not worried about my alternator, I'm worried about the pump always being on (which is not just bad for the electrical system, it makes the steering unnecessarily light).

Bigsyke
11-03-2008, 04:09 PM
You guys are totally missing it - I'm not worried about my alternator, I'm worried about the pump always being on (which is not just bad for the electrical system, it makes the steering unnecessarily light).


Speed activated cutoff switch.

GSXRJJordan
11-03-2008, 04:25 PM
Speed activated cutoff switch.

Much easier said than done. Also, doesn't fix the problem of too much pressure the rest of the time. I don't remember for sure, but I don't think the Nissan VSS sends enough voltage to let me tap that and accurately gauge speed (I think it's somwhere less than 2V AC or some crazy shit, I dont remember)... I guess I can hook up the DMM and see what the voltage is across the two wires.

Bigsyke
11-03-2008, 04:42 PM
Too much pressure is no problem, most racks have a plastic dampener controlled by a spring. IMO its more the drag off the alternator and FSM states low Bat voltage will affect engine operation.

S14DB
11-03-2008, 04:46 PM
Is there any write ups on what PSI and GPM the MR2 pump does at different voltages?

What is the GPM/PSI output of the stock pump at different RPM?

Once you figure this out you can hook up a tach pulse to voltage converter to a motor controller to increase the pump voltage as the rpm increases.

A custom speed and steering angle setup seems like way to much engineering for a simple system.

dirtdiggler666
11-03-2008, 04:47 PM
bill for sure needs to chime in on this one i would love to do this someday

keep this going guys lets figure it out

GSXRJJordan
11-03-2008, 04:57 PM
Is there any write ups on what PSI and GPM the MR2 pump does at different voltages?

What is the GPM/PSI output of the stock pump at different RPM?

Once you figure this out you can hook up a tach pulse to voltage converter to a motor controller to increase the pump voltage as the rpm increases.

A custom speed and steering angle setup seems like way to much engineering for a simple system.

I'm still searching for a diagram/chart showing PSI (they don't ever show flow, because it's minimal in a power steering system apparently) over Input Voltage - I'm actually not sure that the pump is regulated by input voltage, but that's what the Cameron Software writeup said.

The stock power steering pump is a horrible system to emulate, because you don't want more pressure at more RPMs, you want more pressure when you need to turn the wheel fast or lock to lock. A PWM controller is actually extremely simple, as long as it's hooked up to a relay that can switch fast enough, and like I said, fast switching relays that can handle 70a are expensive.

As far as steering angle setup, the Cameron Software site has a blurb from another guy (Jon "Sheer" Pullen) who made a PWM controller, and uses an optical pickup attached to the steering shaft - this is his solution to turning the pump off while you're not turning.

turtl631
11-03-2008, 06:07 PM
Shit, I'd probably kill my battery (PC680) just trying to get out of the ridiculously tight parking spots on my block. 70-90A?! Altima fans draw like 30A at startup IIRC and you definitely notice when they come on. I can't imagine drawing 2-3 times as much current for a longer period.

bbejj123
11-03-2008, 06:12 PM
thats actually what this company i was working for was using on there electric trucks. it worked decently well and if u have the funds it wouldbe a fun upgrade. It didnt have any problems with battery and itwasnt even using an alternator so im sure if u have a working alternator it wouldntbe a problem

Bigsyke
11-03-2008, 06:56 PM
The OEM pump is at some unreal PSI, I would assume a looped 10psi is enough to assist in steering and preventing damage to the U joints.

fueled by hate
11-03-2008, 11:32 PM
Didn't the twin turbo z32 have an electric p/s setup as well?

GSXRJJordan
11-04-2008, 12:40 AM
thats actually what this company i was working for was using on there electric trucks. it worked decently well and if u have the funds it wouldbe a fun upgrade. It didnt have any problems with battery and itwasnt even using an alternator so im sure if u have a working alternator it wouldntbe a problem

Fer realz, they use Electro-hydraulic power assisted steering on lots of big shit. Tractors, back hoes, etc.

The OEM pump is at some unreal PSI, I would assume a looped 10psi is enough to assist in steering and preventing damage to the U joints.

Haha 10psi? The lowest I've ever heard of is 1200psi. I would totally like to put a controller on there to see what pressure actually feels good and helps out though.

Didn't the twin turbo z32 have an electric p/s setup as well?

Electric power steering is different than hydro-electric - the NSX and S2000 have electric power steering, where the electric motor is wrapped around the rack itself - crazy $$$. Hydro-electric uses an electric motor with hydraulic pressure to actually move the rack. I'm guessing that's what you mean, and no, all VG30s have standard power steering.

Shit, I'd probably kill my battery (PC680) just trying to get out of the ridiculously tight parking spots on my block. 70-90A?! Altima fans draw like 30A at startup IIRC and you definitely notice when they come on. I can't imagine drawing 2-3 times as much current for a longer period.

Srsly. That's why I'd throw a couple capacitors in the system too, just to make sure there's not too much loading too fast. I did the math, and with 70A you'd actually 33 Farads of capacitance to fully offset the momentary drain - ouch!

blu808
11-04-2008, 12:57 AM
screw it im gonna make the non power racks I have been talking about.

No cooler
No pump
No lines
No leaks
More power
More room

GSXRJJordan
11-04-2008, 01:17 AM
Dude, I'm totally all ears. We'll have to see how they do with lock-to-lock transitions at speed (eg, drifting), but if you can initiate with one hand and lock-to-lock it in decent time, they'll sell for sure.

blu808
11-04-2008, 03:01 AM
Im sure if you run enough caster it should be fine.

We will see.

CmR333
11-04-2008, 07:43 AM
SUBSCRIBED.. i have an 04 rx8 that im finishing a sr swap in and i have a elec. assist rack that came stock in my car. so upgrading it to somthing differant or a manual rack will be awsome because there is way to much stuff i have to do to get the stock unit to preform decent while driving it daily.

Bigsyke
11-04-2008, 09:19 AM
screw it im gonna make the non power racks I have been talking about.
No cooler
No pump
No lines
No leaks
More power
More room

How is this going to be any better or different than depowering/greasing a rack and adjusting the rod tension? With a depowered rack there is very little drag with the rack outside of the car. Its the caster, and the wheels altering camber when the wheel is turned. essentiallly your pushing a little bit of the car up with the steering wheel.


Haha 10psi? The lowest I've ever heard of is 1200psi. I would totally like to put a controller on there to see what pressure actually feels good and helps out though.


Im running a non powered rack on the s14. Its fine. I think a small ammount of pressure 10-100psi, I got rid of the PS system in the 1st place was because of leaks, feel, power loss and weight.

Dude, I'm totally all ears. We'll have to see how they do with lock-to-lock transitions at speed (eg, drifting), but if you can initiate with one hand and lock-to-lock it in decent time, they'll sell for sure.

s13dan
11-04-2008, 11:16 AM
From my experiences PS>then no PS as far as car control. If you get in a hairy situation id rather save my car and not break my thumbs...

Most racks pressure stay below 100psi but spike dramatically when they are locked.Sometimes reaching above 1000psi, hence why the car will not snap back like what can happen when you do not have power steering.

i am curious about all of this, Get DSG on here!

Oo_Skyline_oO
11-04-2008, 11:44 AM
You guys are totally missing it - I'm not worried about my alternator, I'm worried about the pump always being on (which is not just bad for the electrical system, it makes the steering unnecessarily light).

hmmm. very interesting. I'm with this guy. The best way to do it is to have the pump always on, but at low pressure(6v maybe??) then a sensor to the drive column that detects the speed at witch the column is turning to switch the pump to full power

GSXRJJordan
11-04-2008, 11:56 AM
hmmm. very interesting. I'm with this guy. The best way to do it is to have the pump always on, but at low pressure(6v maybe??) then a sensor to the drive column that detects the speed at witch the column is turning to switch the pump to full power

That's exactly what I'm trying to do. Because there's so much power, you'd have to have a PWM controller attached to a relay, but that's not too difficult. Then a potentiometer to adjust 'max' voltage (which hopefully adjusts max pressure as well), and a steering angle sensor to give you more voltage when you're actually moving the wheel, but cut voltage at full lock. I guess I'd have to use an optical sensor on the column... but what I'm afraid of is that if you are making a constant radius turn (meaning you turn the wheel once, and hold it there), that the sensor would give you power assist as you start the turn, then cut the power assist when the wheel stays stationary throughout the turn, making in increasingly difficult to hold the wheel. Not a big deal at "regular" speeds, but I'm thinking it could be interesting on the bank @ Irwindale, for instance.

The way I've done stuff like this in the past is with a Basic STAMP (simple programmable chip, and I think my breadboard also has a PWM controller because I used motors also) - if I went that route, I'd be able to tell the PWM controller how fast to switch to protect whatever starter relay I end up using.

blu808
11-04-2008, 04:29 PM
Bill at dsg said he would love a correct ratio non power rack. We will be sending him a prototype to test when we get one.

CmR333
11-04-2008, 06:57 PM
any chance of making somthing some what universal? i say this because i dont own a 240 but i really would love a non power rack with a proper ratio

GSXRJJordan
11-04-2008, 07:24 PM
any chance of making somthing some what universal? i say this because i dont own a 240 but i really would love a non power rack with a proper ratio

They're application-specific for the most part. Appleton makes manual racks with different ratios, hit them up for your application.

CmR333
11-04-2008, 07:59 PM
cool thanks. im still going to stick around to see how this works out though. i have a custom built subframe and i can switch steering setups with a little bit of fabricating and welding.

blu808
11-04-2008, 08:42 PM
Since you have an rx8 why not just use a non power fc rack?

CmR333
11-04-2008, 09:02 PM
forgive my ignorance but, an fc rack?

blu808
11-04-2008, 09:07 PM
fc= fc3s rx-7

CmR333
11-04-2008, 10:08 PM
lol ok i just smacked myself for you lol. i thought about it but the tie rods were way off and my stock ones are a different size and thread.

blu808
11-04-2008, 10:11 PM
Fabrication Fabrication Fabrication

CmR333
11-05-2008, 08:36 AM
yes fabrication is the answer but when it comes to steering its not one of my strong points. i wouldent even know where to start with building or modifying the tie rods..any suggestions,,parts materials and so on.

TougeLabs
04-09-2009, 07:28 PM
Im bringing this thread back from the dead. I am sorry for being lazy and never attacking this project. Anyway i was debating on putting a limit switch on the pump something that will let me control the pump itself. I have a turbo miata with a de-powered rack and i love it. Its just gangster as hell.

GSXRJJordan
04-09-2009, 10:19 PM
I gave up on the project, after looking at the OEM control diagram. To do it right (like the MR2, S2000, and NSX do it), you not only need a speed-activated cutoff switch (so you have no power steering at freeway speeds/similar), you need a PWM controller hooked up to the steering wheel so it only gives you max pressure when you're actually turning the wheel - can't just be based on steering angle, or it would go dead on you during a constant radius turn.

After looking into photo-diodes and encoders to wire into a PWM run by a BASIC stamp board, I decided that I'd give regular P/S another go, and it's not too bad with good OEM components and a cooler (and a sweet polished aluminum reservoir by LuisGonz).

CLIFFS: if you can get the MR2 controller (2 pieces I believe) AND pump, and a diagram to wire it into your stock VSS, I'd try that - otherwise you'll have a pump that's always on, drawing up to 70A

TougeLabs
04-09-2009, 10:38 PM
I need to talk to Bill...Bill!! Chime in

CmR333
04-10-2009, 06:34 PM
i actually have a whole spare mr2 now that has eps. im rmepted to try and work it into my rx8 because i have no room to add a p/s pump. im going to consult the big green mr2 book and see if there is some way i can make the stock mr2 components and mod them to fit an aftermarket steering wheel and a sr20. we will see

GSXRJJordan
04-10-2009, 06:42 PM
if you scan in the pages and host them, I'll take a look and tell ya what needs to be tied in and how to do it, if possible :) I'm really curious.

CmR333
04-10-2009, 08:08 PM
sounds like a plan it might take me a while to find it all, im kinda missing the index but im sure i can locate the needed info.maybe you could look into getting the mr2 control module to power the showa eps rack in my car....just a thought.

TougeLabs
04-11-2009, 11:00 AM
would you like to sell that eps ?? :)

driftstyre
04-15-2009, 06:40 PM
If I were to do it again, I would get a manual rack and then an electric power assisted steering column. They came in the Vauxhaul/Opel Corsa, Fiat Punto, Pug 106, VWs, BMWs and a ton of other small vehicles in europe and can be had for a couple hundred dollars. You can then get an aftermarket ecu that controls assist by a dial or by speed ($100). Search for electric power steering on ebay uk and you'll get hundreds of them.

GSXRJJordan
04-15-2009, 06:48 PM
If I were to do it again, I would get a manual rack and then an electric power assisted steering column. They came in the Vauxhaul/Opel Corsa, Fiat Punto, Pug 106, VWs, BMWs and a ton of other small vehicles in europe and can be had for a couple hundred dollars. You can then get an aftermarket ecu that controls assist by a dial or by speed ($100). Search for electric power steering on ebay uk and you'll get hundreds of them.

Bill, you finally made it into this thread!

I'll definitely be looking into that :) I had hoped to stick with the stock rack (or something that bolts in the same location) but I guess steering rack mounts wouldn't be such a huge deal to fab.

Bigsyke
04-15-2009, 06:58 PM
The draw on the alternator trying to maintain the battery would be the same draw as the OEM PS pump.

halllon
06-28-2012, 03:48 PM
Does anyone know the flow rate (GPM) and bypass pressure of the MK2 and MK3 MR2 power steering pumps? I need to find out if it already pushes or can be modified to push over 3 Gallons per minute and have about 1600 psi bypass pressure.

GSXRJJordan
06-28-2012, 03:51 PM
Does anyone know the flow rate (GPM) and bypass pressure of the MK2 and MK3 MR2 power steering pumps? I need to find out if it already pushes or can be modified to push over 3 Gallons per minute and have about 1600 psi bypass pressure.

The bypass is adjustable IIRC, and 1600psi is within normal PS pump range. It's been a long time since I've looked at the measurements, but I believe it flows over 3gpm, but the flow rate is related to pressure - I doubt it's 3gpm @ 1600psi.

halllon
06-28-2012, 05:16 PM
The bypass is adjustable IIRC, and 1600psi is within normal PS pump range. It's been a long time since I've looked at the measurements, but I believe it flows over 3gpm, but the flow rate is related to pressure - I doubt it's 3gpm @ 1600psi.

Thanks Jeff, this is the 1991 to 1998 or so pump without reservoir, correct? I found a couple of other forum posts that stated it bypasses at 2000 psi (I don't know if this is how they're set from factory, though).

PoorMans180SX
06-28-2012, 05:28 PM
I'm pretty sure the MR-S pump is has an internal load sensor, and thus does not always consume 70amps. You don't even need the steering angle sensor for this to work.

Also, Matt Powers uses the old MR2 pump without any controller it seems, and he doesn't seem to be having issues. I could be wrong of course.

Mishkin_707
06-29-2012, 12:01 AM
This is a real interesting subject, iirc, the mid 2000's chevy Malibu had electronic power steering, has anyone looked into this?